diff --git a/ggsn_tests/GGSN_Tests.ttcn b/ggsn_tests/GGSN_Tests.ttcn
index b3e26d5..ecc7d7a 100644
--- a/ggsn_tests/GGSN_Tests.ttcn
+++ b/ggsn_tests/GGSN_Tests.ttcn
@@ -10,12 +10,19 @@
 	import from GTPU_Types all;
 	import from IP_Types all;
 	import from ICMPv6_Types all;
+	import from Native_Functions all;
 
 	const integer GTP0_PORT := 3386;
 	const integer GTP1C_PORT := 2123;
 	const integer GTP1U_PORT := 2152;
-	const charstring g_bind_ip_c := "127.23.42.1";
-	const charstring g_bind_ip_u := g_bind_ip_c;
+
+	modulepar {
+		charstring m_bind_ip_gtpc := "127.23.42.1";
+		charstring m_bind_ip_gtpu := "127.23.42.1";
+
+		charstring m_ggsn_ip_gtpc := "127.0.0.6";
+		charstring m_ggsn_ip_gtpu := "127.0.0.6";
+	}
 
 	type set PdpContext {
 		hexstring	imsi,
@@ -44,11 +51,11 @@
 
 		var OCT1 g_restart_ctr := '01'O;
 		/* FIXME: unify with g_bind_ip + parse from config file */
-		var OCT4 g_sgsn_ip_c := '7f172a01'O;
-		var OCT4 g_sgsn_ip_u := '7f172a01'O;
+		var OCT4 g_sgsn_ip_c;
+		var OCT4 g_sgsn_ip_u;
 		/* FIXME: parse remName from config file */
-		var GtpPeer g_peer_c := { connId := 0, remName := "127.0.0.6", remPort := GTP1C_PORT };
-		var GtpPeer g_peer_u := { connId := 0, remName := "127.0.0.6", remPort := GTP1U_PORT };
+		var GtpPeer g_peer_c := { connId := 0, remName := m_ggsn_ip_gtpc, remPort := GTP1C_PORT };
+		var GtpPeer g_peer_u := { connId := 0, remName := m_ggsn_ip_gtpu, remPort := GTP1U_PORT };
 		timer T_default := 3.0;
 
 		/* next to-be-sent GTP-C sequence number */
@@ -63,14 +70,17 @@
 		}
 		g_initialized := true;
 
+		g_sgsn_ip_c := f_inet_addr(m_bind_ip_gtpc);
+		g_sgsn_ip_u := f_inet_addr(m_bind_ip_gtpu);
+
 		var Result res;
 		map(self:GTPC, system:GTPC);
-		res := GTP_CodecPort_CtrlFunct.f_IPL4_listen(GTPC, g_bind_ip_c, GTP1C_PORT, {udp:={}});
+		res := GTP_CodecPort_CtrlFunct.f_IPL4_listen(GTPC, m_bind_ip_gtpc, GTP1C_PORT, {udp:={}});
 		log("GTP1C ConnectionID: ", res.connId);
 		g_peer_c.connId := res.connId;
 
 		map(self:GTPU, system:GTPU);
-		res := GTP_CodecPort_CtrlFunct.f_GTPU_listen(GTPU, g_bind_ip_u, GTP1U_PORT, {udp:={}});
+		res := GTP_CodecPort_CtrlFunct.f_GTPU_listen(GTPU, m_bind_ip_gtpu, GTP1U_PORT, {udp:={}});
 		g_peer_u.connId:= res.connId;
 
 		g_restart_ctr := f_rnd_octstring(1);